High-Performance Hybrid Racing K Series Valve Cover Breather Filter

K-Series Crankcase Breather Filter – Clean Air Inlet for OEM-Style PCV Systems

Designed specifically for Honda K-series engines (K20/K24), this crankcase breather filter replaces the stock valve cover breather port fitting, allowing clean, filtered air to enter the crankcase as part of a properly functioning PCV (Positive Crankcase Ventilation) system.

Key Features:

• Direct fit for Honda K-series valve cover breather port (16–19mm inlet diameter)
• High-flow, washable filter media keeps dust and debris out
• Durable, oil-resistant construction with secure clamp-on mounting
• Maintains clean airflow into the crankcase under proper PCV function
• Ideal for naturally aspirated, stock, or mildly modified engines

How It Works:

In a stock or properly maintained PCV system, crankcase ventilation operates on a closed-loop design. As combustion occurs, a small amount of pressure (blow-by) slips past the piston rings into the crankcase. This pressure is pulled out through the PCV valve into the intake manifold under vacuum.

To maintain airflow and pressure balance, filtered outside air must re-enter the crankcase, typically through the valve cover breather port. Our breather filter ensures this incoming air is clean and free from contaminants — protecting internal engine components and supporting efficient crankcase scavenging.

Important Note for Modified Engines:

If your engine is turbocharged, supercharged, high-compression, or experiencing excessive blow-by, this filter should not be used as a vent outlet. In those setups, crankcase pressure is often too high for the stock PCV system to handle. We strongly recommend installing an oil catch can system with proper routing to manage pressure and oil vapor safely and effectively.

Applications:

• Honda K20 / K24 Engines
• Naturally Aspirated or Mild Bolt-On Builds
• OEM or Lightly Modified PCV Systems